JavaScript - Testing with Jest

Overview

Estimated time: 10–15 minutes

Jest is a popular JavaScript testing framework for unit and integration tests.

Learning Objectives

• Write and run tests using Jest.
• Understand basic Jest features and assertions.

Prerequisites

• JavaScript - Multimedia & Image Maps

Jest Example

// sum.js
function sum(a, b) {
  return a + b;
}
module.exports = sum;

// sum.test.js
const sum = require('./sum');
test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

Common Pitfalls

• Tests should be isolated and repeatable.

Summary

Jest makes testing JavaScript code fast and easy. Use it for reliable, maintainable code.